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Chapter 7 Cholinoceptor-Blocking Drugs ( Ⅱ ) -N - Cholinoceptor blockers. Zhang bin Institute of Pharmacology School of Medicine Shandong University. Nicotinic cholinoceptor- blocking drugs. N N -R antagonists (ganglionic blocking drugs) N M -R antagonists - PowerPoint PPT Presentation
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Chapter 7 Cholinoceptor-Blocking Drugs
(Ⅱ ) -N -Cholinoceptor blockers Zhang bin
Institute of Pharmacology
School of Medicine
Shandong University
Nicotinic cholinoceptor- blocking drugs
NN-R antagonists
(ganglionic blocking drugs)
NM-R antagonists
(neuromuscular blocking drugs )(Skeletal muscle relaxants)
Section1 NN-R antagonists
(ganglionic blocking drugs)
Mecamylamine(美卡拉明,美加明 )
Trimethaphan(樟磺咪酚,曲美芬)
NN-R antagonists
[Characteristics]
Co-innervation and dominant theory Blood vessel: vasodilation, peripheral
resistance decrease, blood pressure decrease. Glands, eye, GI, bladder: dry mouth,
mydriasis, constipation, urinary retention
[Clinical use] HBP
Section2 NM-R antagonists ( Skeletal muscle relaxants )(neuromuscular blocking drugs )
Depolarizing skeletal muscle relaxants
—— succinylcholine Nondepolarizing skeletal muscle
relaxants
—— D-tubocurarine
Depolarizing skeletal muscle relaxants
Mechanism: Two-phase blockPhase 1: durable depolarizing blockPhase 2: NM receptor desensitization
Depolarizing skeletal muscle relaxants
[Characteristics of Action]
( 1 ) Muscle fasciculation ( 肌束震颤 )( 2 ) Tachyphylaxis ( 快速耐受性 )
( 3 ) Can’t be antagonized by AChEI
( 4 ) have no ganglionic blocking actions at therapeutic dose
(5) rapid onset and short duration
succinylcholine (琥珀胆碱 ,scoline,司可林 )
(1)Onset rapid(1’), Emax 2’, short duration(5’)
(2) Neck and limbs
(3)pseudocholinesterase
[Uses]
1.assistant agents of anesthetics
2.bronchial cannulation , bronchoscopy
oesophagoscop(食道镜 )
Adverse reactions
(1) asphyxy(窒息 ): respiratory muscle paralysis: genetic pseudo-ChE low patients anti-AChE agents local anesthetics and aminoglycosides
(2) Muscle fasciculation (3) Elevation of extracellular K+
(4) CVS: complex (5) Malignant hyperpyrexia(恶性高热 ): idiosyncrasy (特异质反
应 ) (6) increase histamine release
Malignant hyperpyrexia 在并用琥珀胆碱和强挥发性全麻药(氟烷、
异氟烷)时引起的高代谢反应,体温极度升高。是一种常染色体显性遗传。 ( 钙释放通道基因变异,骨骼肌对钙呈高反应性,引起剧烈的肌肉收缩、代谢提高 )
丹曲林钠 ( 肌松剂 ): 其主要作用部位是骨骼肌的肌浆网,通过抑制肌浆网释放钙离子而减弱肌肉收缩。
Nondepolarizing muscular relaxants(competitive neuromuscular blockers)
Mechanisms:
NM-R competitive
antagonist
Characteristics of Action (1) no fasciculation (2) Antagonized by AChEI (3) slow onset and long duration (4) NN blockade at therapeutic dose
d-tubocurarine(筒箭毒碱 )
[[Actions] muscle relaxant block ganglionic release histamine
[Uses]
assistant agents of anesthetics
Other drugsbenzylisoquinolines (苄基异喹啉类 ) Atracurium (阿曲库铵 ) Doxacurium (多库铵 ) Mivacurium (米库铵 )ammoniosteroids(类固醇胺类) Pancuronium (泮库铵 ) Pipecuronium (哌库铵 ) Rocuronium (罗库铵 ) Vecuronium (维库铵 )